Patrons of Foxwoods Casino in Mashantucket, Conn., play in the gaming area of the casino. As table game dealers vote on a proposed union contract with Foxwoods in September 2013, smoking in the giant entertainment complex is an issue.

MASHANTUCKET, Conn. — The smell of cigarette smoke hung heavily over the Great Cedar Hall at Foxwoods Resort Casino one recent weekday morning, as gamblers lit up freely in the cavernous slot machine room. Ventilation that workers say has improved over the years was keeping the smell to a minimum and eliminating what might otherwise have been clouds of smoke hanging over the giant room.

Though a union contract will bring table game dealers increased wages and other benefits, workers will still have to breathe in gamblers’ smoke. Because Indian sovereignty prevails, state law banning indoor smoking in most Connecticut businesses does not apply to Foxwoods, which is owned by the Mashantucket Pequot tribe.

The employees’ union, the United Auto Workers, has been able to negotiate improved air filters and regular maintenance schedules.

“It’s part of the job,” said Kathleen McNamara, a server who has worked at Foxwoods for 10 years.

Some areas at Foxwoods are reserved for nonsmokers, and McNamara — a smoker who’s trying to quit — said she can spend some time in smoke-free environments during her six-hour shift. Still, she said she’s happy with her work.

In the contract overwhelmingly ratified by workers in recent voting, the UAW won an 11.5 percent wage increase over four years and the right for dealers to decide how to distribute tips.

But state Sen. Terry Gerratana, Senate chairwoman of the legislature’s Public Health Committee, said lawmakers are stymied by tribal law, which can dictate things like smoking.

“It’s like us telling Ireland what they can and can’t do,” she said.

Foxwoods did not respond to a request for comment.

Without a law in its toolbox, the state negotiated voluntary agreements several years ago with Foxwoods and neighboring Mohegan Sun that limit smoking areas. Then-Gov. M. Jodi Rell worried in 2009 about the prospect of a legal battle and the loss of hundreds of millions of dollars in slots revenue. The Mohegan tribal chairman threatened to withhold the state’s share of slot machine revenue over a possible smoking ban and to sue in federal court.

Full smoking bans are not common at commercial casinos. The prospect of lost revenue has prodded local and state officials to exempt casinos from full smoking bans that are in place nearly everywhere else.

Pennsylvania law allows casinos to permit smoking on 50 percent of gaming floors.

Local law in Atlantic City, N.J., restricts smoking to no more than 25 percent of casinos and Nevada bans smoking in all areas of grocery and convenience stores, including gambling areas. But the state allows smoking in casino gambling areas where children are barred by law from loitering.

Nevada casinos also may designate separate areas such as poker rooms to be smoke-free.

Cynthia Hallett, executive director of Americans for Nonsmokers’ Rights, said smoking in casinos is an issue because the number of casinos is increasing in the United States.

“We have a growing workforce exposed to secondhand smoke,” she said, adding that “ventilation can only do so much.”

David Schwartz, director of the Center for Gaming Research at the University of Nevada at Las Vegas, said revenue has fallen in several states that banned smoking at casinos. As a result, lawmakers are reluctant to impose further restrictions, he said.

A significant, but unspecified, portion of gamblers smoke, leading researchers to see a link between smoking and gambling, Schwartz said.

“You gamble longer if you’re smoking,” he said.

For example, Atlantic City’s Revel Casino-Hotel, which is competing with other casinos in the city known for gambling, is allowing smoking on the casino floor for the first time as one strategy to hold on to customers. A spokeswoman said the casino would not comment.

A Montana ban on smoking in taverns and casinos resulted in a steep revenue drop. In the state’s 2010 budget year immediately after the ban took effect, video gambling machine taxes were $52.4 million, a 16 percent decline from the previous year.

Rick Ask, administrator of the Gambling Control Division of the Montana Department of Justice, said the weak economy was a factor but most of the revenue drop was the result of the state smoking law.

But casino operators don’t believe they are losing potential customers as a result of smoking limits or bans, Ask said.

“Most would say, ‘Those are not my customers,”’ he said.

Clyde Barrow, director of the Center for Policy Analysis at UMass Dartmouth, said studies disprove the industry’s argument that smokers gamble more frequently than nonsmokers. And he contended the recession and weak economic recovery — not smoking — are to blame for falling casino revenue.